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O2 Flushing During Deco

I have been trying to become more efficient with my gas consumption. Along these lines, I am thinking about O2 flushing procedures that balance offgassing with gas consumption.

So far, what I am doing is flushing with oxygen two or three times upon arrival at my 20 foot stop. Then, considering that I am probably offgassing a fair amount of Helium, I flush again after two to three minutes. After that, I flush after about five more minutes. Then, I might do it again after about ten minutes.

I was just curious as to how often everyone flushes with oxygen upon arrival at the shallow stop. Maybe I am doing some overkill here.

Re: O2 Flushing During Deco

I dive a classic kiss and I always turn of my dil when I get to my 6m stop and flush 3 times, I find this works for me. I then push the PP02 up to 1.4 I dive with a VR3 set to 1.2 I then push it up again when it starts to drop below 1.25/1.3.

Re: O2 Flushing During Deco

when on deco from 6m ans some tine 9m I close the hydrogom and connect ADV on an external O2 bottle ( so dont need to reboost my smalls inboard O2 bottle too frequently ).
Then I notice that is quite impossible to have a stable higher PPO2 than 1.3 at 6m (till the level of inert gas is high inside my body I think ).
But at the end of the deco ( I always use very conservative tables except if I have some problem, then turn on a shorter way) I notice that I get a good 1.6 and I am very pleased when I can go out water in such a situation ( guess I have done a good and rather complete deco , if no error done before).

Re: O2 Flushing During Deco

I don't flush with O2 much anymore. I ususlly run my Classic Kiss at about 1.2 during the dive and 1.3 to 1.4 on deco. I have found on some deeper/longer dives that the high PO2 I was using on ascent was giving me a high CNS.
I would prefer to hang just a couple of minutes longer than push the CNS. I have not found the difference worth the risk.

I do however flush one at the end of my dive to check cells and prepare the unit to have a high PO2 on the surface as I get onboard the boat.

Louis, I'm not sure that tuning off the dil is such a great idea. Especially if you are flushing the loop with O2. What if you needed to do a quick flush if you felt like you had symptoms of oxtox? Or if you needed to do a quick descent to help someone and forgot to turn it back on?

Re: O2 Flushing During Deco

Originally Posted by Marc T

But at the end of the deco ( I always use very conservative tables except if I have some problem, then turn on a shorter way) I notice that I get a good 1.6 and I am very pleased when I can go out water in such a situation ( guess I have done a good and rather complete deco , if no error done before).

Watching for a stable PO2 is a nice way of checking you've done enough deco.

Re: O2 Flushing During Deco

Originally Posted by Peter Piemonte

I'm not sure that tuning off the dil is such a great idea. Especially if you are flushing the loop with O2. What if you needed to do a quick flush if you felt like you had symptoms of oxtox? Or if you needed to do a quick descent to help someone and forgot to turn it back on?

How long does it take to turn the tank on ? About 1 sec ?

You can't effectively descent if your diluent is not pressurized because you won't be able to get a full breath in just a few meters. Then reach back and turn the tank on while carry on with the descent...